Next Article in Journal
A Multi-Convolutional Autoencoder Approach to Multivariate Geochemical Anomaly Recognition
Next Article in Special Issue
Re-Thinking Mining Waste through an Integrative Approach Led by Circular Economy Aspirations
Previous Article in Journal
An Integrated Analytical Approach to Define the Compositional and Textural Features of Mortars Used in the Underwater Archaeological Site of Castrum Novum (Santa Marinella, Rome, Italy)
Previous Article in Special Issue
Effect of High Mixing Intensity on Rheological Properties of Cemented Paste Backfill
Article Menu

Export Article

Open AccessArticle

Recovery of Alkali from Bayer Red Mud Using CaO and/or MgO

1,2,3,4, 2,3,*, 2,3, 2,3 and 2,3
1
School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
2
Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
3
National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
4
National Engineering Research Center of Distillation Technology, Tianjin 300072, China
*
Author to whom correspondence should be addressed.
Minerals 2019, 9(5), 269; https://doi.org/10.3390/min9050269
Received: 29 March 2019 / Revised: 22 April 2019 / Accepted: 26 April 2019 / Published: 30 April 2019
  |  
PDF [3514 KB, uploaded 30 April 2019]
  |  

Abstract

Recovering alkali from Bayer red mud is crucial for storage security, resource utilization and environmental protection. In this study, the addition of MgO and/or CaO was conducted to recover alkali from red mud with a hydrothermal method for the first time. A synergistic result with a residual Na2O/SiO2 weight ratio of 0.03 was obtained by adding the blend of CaO and MgO at an appropriate temperature. MgO was found to be more temperature-dependent than CaO when substituting Na2O from red mud due to their different hydration processes. The alkali recovery was controlled by a reaction at a temperature of <200 °C and by internal diffusion at a higher temperature for MgO, but controlled by internal diffusion for CaO in the whole temperature range studied. The formation of hydrotalcite-like compounds with a loose structure was verified with the help of XRD, FTIR, and SEM-EDS. It was proved that both the reaction kinetics and the characteristics of solid products have a significant influence on the recovery of alkali. View Full-Text
Keywords: recovering alkali; Bayer red mud; reaction kinetics; magnesium oxide; hydrotalcite-like compounds recovering alkali; Bayer red mud; reaction kinetics; magnesium oxide; hydrotalcite-like compounds
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

Supplementary material

SciFeed

Share & Cite This Article

MDPI and ACS Style

Zhou, B.; Cao, S.; Chen, F.; Zhang, F.; Zhang, Y. Recovery of Alkali from Bayer Red Mud Using CaO and/or MgO. Minerals 2019, 9, 269.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Minerals EISSN 2075-163X Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top